The proposed research program of three related studies focuses on: (1) factors hypothesized to be responsible for the emergence of gender differences in depressed affect during adolescence and (2) the long-term implications for mental health trajectories established in early adolescence. All three studies will test the general hypothesis that the developmental paths taken in early adolescence become enduring mental health patterns, with differences for boys and girls. The program of research is based on a model of the development of mental health derived from our previous research that emphasizes gender differences in the challenges experienced during the early adolescent transition, in resources available to children to help them cope with these challenges, and in individual styles of coping with these challenges, hypothesized to be related to sex role identification. Each study examines issues key to this general model. Three studies are proposed: Study 1 examines the longer-term significance of early adolescent patterns: Study 2 investigates the developmental patterns and correlates of adjustment across early and middle adolescence; and Study 3 examines the specific coping processes that moderate the effects of early adolescent developmental challenges on the development of depression. Study 1 is a follow-up assessment of our original sample at a late college age when most are about to make a transition into adult roles. We have previously studied these individuals in 6th, 7th,8th and 12th grades. Assessment at this later age, of constructs measured previously, will provide information about the long-term implications of developmental trajectories in early adolescence. Study 2 extends our previous work by: (1) testing whether our previously obtained 12th grade gender differences are found in a similar sample: (2) testing hypotheses about developmental patterns in 9th through 12 grades based on inferences from our previous work; (3) evaluating our hypotheses about the causes of the emergence of gender differences during this period; and (4) identifying children at risk for developing depression using classification techniques developed from our original sample. Study 2 will use a short-term cohort-sequential design to examine the development from 6th to 12th grade of the patterns and correlates of adjustment across early and middle adolescence. The third study is a two-year longitudinal investigation of; (1) the development of coping responses to challenge in the early adolescent transition and (2) the relationships of such responses to adjustment and the development of depression. The design of study 3 involves the comparison of youngsters at high and normal risk of developing depression during adolescence. In summary this program of research is designed to examine factors related to the development of gender differences in mental health.